Just managed to get a firing lever for my 2 inch mortar at long last but have misplaced the small nut that holds it to the lever shaft. I need to find out the thread size of the small nut so i got the thread gauge out and measured the diameter of the threaded shaft but found that i could not match the tpi up with the gauge. The thread diameter worked out about 4.2 on the vernier. Anyone know what thread size this nut is, not sure if its a BSW thread. I also need the nut diameter or the AF size (across the flats as its known) flat side to flat side.
